HomePNA or HPNA is a de facto home networking standard developed by the Home Phoneline Networking Alliance. HPNA allows all the components of a home network to interact over the home's existing telephone wiring without disrupting voice capability. In the same way a LAN operates, home networking processes, manages, transports and stores information, which enables disparate devices in a home network such as telephones, fax machines, desktops, laptops, printers, scanners and Web cameras to connect and integrate over an existing wiring topology.
To create the home network, personal computers may be equipped with a HPNA network and HPNA software. An HPNA network may be implemented as an internal PC network interface card (NICs) that includes telephone jacks on the back for connection to the network. An HPNA network may also be implemented in an external USB adapter that plugs into the USB port on the PC on one end, while the other end connects to the phone line at the wall jack. Additionally, an HPNA network may be implemented as part of the chipset or ACR (Advanced Communications Riser).
FIG. 1 illustrates an embodiment of a home phone line network that complies with the Home Phoneline Networking Alliance (HPNA) specification version 2.0. The network allows multiple computers to communicate through telephone wires typically installed in residential homes. The network includes an application program running on the PC called a host media access controller (MAC) 112, and a control chip 100 for implementing the HPNA 2.0 specification that is included on a network interface card. The control chip 100 includes a Media Independent Interface (MII) 106, a Media Access Controller (MAC) 108, and a Physical Layer (PHY) 110.
The host MAC 112 sends data packets out over the home network, and receives data packets from the network, through the control chip 100. The controller chip 100 communicates with an analog front end (AFE) 104 that processes signals between the chip 100 and the transmission medium, which in this case are the telephone wires of the house that are accessed via a phone jack 102. The AFE 104 converts outgoing digital signals into analog signals, and converts incoming analog signals into digital signals.
When the host MAC 112 transmits a data packet over the telephone wires, it is possible that another device on the network may be in the process of transmitting a data packet. This situation may result in a packet collision, which degrades overall network performance.
Accordingly, the transmission of the data packets from the host MAC 112 needs to be deferred until after the transmission medium is no longer busy. Further, there is a need to verify that the transmission of the data packets are being deferred without monitoring activity on the transmission medium. The present invention addresses such needs.